Circuit board



FIG. 1 is a perspective view of a circuit board, showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof.

The broken lines shown in the drawings depict environmental structure or portions of the article that form no part of the claimed design. 

CLAIM The ornamental design for a circuit board, as shown and described. 